1. Field of the Invention
This invention relates to apparatus for adjusting the position of a rotatable cutter mechanism and more particularly to apparatus for turning the timing belt of the drive mechanism to angularly displace the driven pulley of the cutter shaft in a preselected direction to change the angular position of the cutter blade with respect to a moving web to be cut.
2. Description of the Prior Art
Cutter mechanisms for cutting notches of a selected length in a moving web as illustrated and described in U.S. Pat. No. 3,782,233 disclose a pair of rotatable cutting knives that are positioned on opposite sides of the web. The cutting knives are nonrotatably secured to rotatable shafts that are mounted on a platform connected through coupling devices to gear boxes that are drivingly connected to a common drive shaft.
It is essential that in forming the side edges of the seal flap and the bottom flap of the envelope blank to be formed from the web that the cutting knives on opposite sides of the web rotate in timed relationship to each other so that the notches cut in the web are cut at the same transverse location on the web. If the rotating knives should be out of phase, the notches formed on opposite sides of the web will not be symmetrical and an adjustment in the phase relationship of the cutting knives is required to accurately cut notches in the moving web. Adjusting the relative position of the cutting knives so that the cutting sequence of the knives be in phase or coordinated so that the notches be oppositely positioned is accomplished by either disengaging the cutter shaft from the driven pulley and rotating the cutter shaft through the required angular displacement to provide the proper register between the cutter shafts or to drivingly connect the driven pulley to the drive pulley by relatively complex gearing in order to change the timing of the cutter shaft. Because the known rotating blade-type cutters are mechanically connected to a common drive shaft, it is not possible to adjust the phase relationship between the cutting knives while the web is moving and the cutter mechanism is operating.
There is need for apparatus to adjust the phase relationship of the cutting knives of a rotatable cutter mechanism for cutting notches in the opposite sides of a moving web. While it has been suggested by the prior art systems to adjust the relative position of the cutter knives with respect to the web so that the knives cut the web at the same transverse location, complex gearing connecting the drive shaft to the cutter shaft is required. Furthermore, it is not possible to perform the phase adjustment without either disconnecting the driven pulley from the cutter shaft or stopping movement of the web.